supplements with phentermine

Common Supplements with Phentermine

General Phentermine Questions?
Check out the ultimate guide to phentermine weight loss pills!

One of the most commonly-discussed topics in our Facebook groups is the use of supplements with phentermine prescription. Do you take extra supplements, or have you been thinking about it? Some of the products most mentioned by users are melatonin, pre-workout, B12, CLA and capsicum. Here we’ll discuss the popularity and general advisability of taking these popular supplements with phentermine!

IMPORTANT: ALWAYS ask your prescribing doctor and pharmacist before combining ANY additional medications or supplements with phentermine. A medical professional is the best person to assess the likelihood of possible drug interactions or negative side effects, especially given your individual medical condition and other prescription & OTC medications.

phentermine and melatonin

Melatonin and Phentermine

Many phentermine users are drawn to melatonin as a sleep aid if they struggle with phentermine-related insomnia. However, you should always ask your doctor before combining melatonin and phentermine given the substances’ opposite effects.

What is melatonin?

Melatonin is a hormone that controls your sleep-wake cycles. It’s made naturally in your brain’s pineal gland, but you can also take it as a dietary supplement. Melatonin supplements are available as pills, gummies or sub-lingual tabs. Available doses range from 1-10 milligrams. [1]

This supplement is commonly used for adjusting sleep schedules. People take melatonin to cope with shift changes, jet lag, insomnia or other sleep disorders. Researchers are also still looking into other uses for this hormone. While it works very well for some users, others note little to no difference when using melatonin.

Even though melatonin is generally better-tolerated than other sleep aides, it’s not harmless. Melatonin can cause daytime sleepiness, headaches, dizziness, stomach discomfort or mood changes (anxiety, depression or crankiness). It can also cause problems if you take it at the same time as other medications including blood thinners, immunosuppressants, diabetes medications or birth control pills. [2]

Can I take melatonin and phentermine together?

The interaction between phentermine and melatonin remains undefined. Some sources warn that phentermine increases alertness, while melatonin dampens it. As a result, it’s not advisable to mix them without a medical professional’s advice. However, some doctors do specifically prescribe melatonin to phentermine patients who struggle with insomnia. If you’re interested in taking melatonin and phentermine together don’t be shy about bringing it up to your doctor and/or pharmacist!

VERDICT: Ask your doctor and pharmacist before combining melatonin and phentermine. Some people may experience a negative drug interaction, so you should discuss the combination with a medical professional before taking melatonin and phentermine at the same time.

Instead of Melatonin

Struggling with insomnia from phentermine, but not interested in (or not permitted to take) melatonin supplements? Here’s a few tricks to make getting some shut-eye a little easier:

  • Take your phentermine early in the morning. The stimulant effects of phentermine will keep you up if you take your pill too late in the day.
  • Avoid caffeine. You should avoid mixing caffeine and phentermine anyway (since they’re both stimulants), but be extra-certain to skip that afternoon coffee or tea if you’re having trouble sleeping.
  • Break a sweat. Research shows that regular exercise anytime except late-evening helps us catch some zzz’s. Get the go-ahead from your doctor and then get started with your phentermine exercise plan!
  • Turn off all your electronics an hour before bed. Read a book, do some light stretching/yoga, listen to music or take a warm shower to help yourself relax.
  • Write it down. Do you lay awake with to-do lists, worries and what-ifs swirling around in your head? If so, take a few minutes each night to jot all your thoughts down on paper and de-stress.

supplements with phentermine and preworkout

Phentermine and Pre-Workout Supplements

As we all know, exercise is critical to weight loss success with phentermine. It makes sense, then, that many people wonder about combining phentermine with pre-workout supplements to give their gym session an extra boost.

What is pre-workout?

Pre-workout supplements, commonly referred to as “pre-workout”, are powders that fitness enthusiasts take just before exercise to enhance performance. Different brands contain different ingredients, but popular ingredients include quick-digesting carbs, amino acids and B vitamins. Some products also contain caffeine or special ingredients like beet juice. These supplements claim to improve performance by boosting energy, and in some cases revving your metabolism or boosting your ‘fight or flight’ response. However, experts conclude that these products do not generally live up to their packaging claims. [3]

Can I take phentermine and pre-workout together?

It’s best to steer clear of pre-workout supplements while taking phentermine. Since phentermine already boosts energy by promoting a biological response similar to ‘fight or flight’, taking a pre-workout supplement is often just taking more of the same (and not in a good way). This combination could cause or exacerbate side effects like rapid heart rate or spikes in blood pressure. Since you don’t know how your body will react, and since every pre-workout supplement is different, taking phentermine and pre-workout together isn’t generally a good choice. This same logic is why healthcare providers ask you to minimize or avoid caffeine while taking phentermine.

VERDICT: Skip the pre-workout supplements while taking phentermine. If you feel like you need an extra energy boost during your gym sessions, check out the tips below or ask your doctor about adjusting your phentermine dosing schedule to better accommodate your workout schedule. Some people find that exercising just after taking phentermine allows them to harness the pill’s energy boost to workout harder.

Instead of a Pre-Workout Supplement

Do you have trouble summoning the energy to work out? Here’s a few ideas to boost your energy and set-up your workout for success, without the help of pre-workout supplements.

  • Schedule your workout around the time you feel the greatest energy boost from phentermine. Many people feel this rush within the first couple of hours after taking the pill, so consider exercising first thing in the morning.
  • Fuel yourself for workout success! Ever arrived at the gym, or started your hike, and then realized you haven’t eaten in hours and have absolutely no energy left to push yourself? If you find yourself hitting a wall during workouts, take care to ensure you’re properly nourished and hydrated beforehand. While taking phentermine it’s extra-important to stay on top of proper hydration and eat regularly to minimize unwanted side effects. If you need a little inspiration, here are a few ideas for healthy pre-workout snacks and easy, two ingredient snacks.
Curious about combining supplements with phentermine? Check out this infographic for a quick summary of 5 popular combinations.

Phentermine and B12 Supplements

Among Facebook group members, B12 (or a complex of B vitamins) is probably the most popular of the supplements with phentermine. In fact, weight loss doctors frequently prescribe B12 shots or pills with phentermine to boost patients’ energy and metabolism. Still, not all experts are convinced about this popular supplement’s true usefulness.

What are B12 supplements used for?

B12 is a water-soluble vitamin found in most animal products (eggs, fish, meat, dairy, etc.). It’s critical for the amino acid conversion that allows for RNA, DNA, protein and lipid synthesis. It also supports proper neurological function and hemoglobin formation. While B12 deficiency is relatively rare amongst healthy American adults, it is more common among older adults, vegans and people with gastrointestinal disorders. [4]

As part of their typical weight loss program, many weight loss clinics offer B12 supplementation (typically via injection or oral supplement) to boost energy and metabolism. Despite this common practice, one expert notes that extra B12 probably won’t help much for weight loss or energy unless you’re deficient. [5] Still, many doctors prescribe this supplementation to combat a potential deficiency. So, if you’re interested in a boost of B12 to support your weight loss journey with phentermine, bring it up to your prescribing doctor!

Can I take phentermine and B12 together?

Yes. Many phentermine patients take phentermine and B12 together, but almost always under the direct supervision of their doctor. While this vitamin is not likely to cause toxicity, it does interact with some medications. Always tell your prescribing doctor about all of your current & recent medications and supplements to minimize the risk of a negative drug interactions. If you’re taking any medications for an acidy stomach, or metformin to manage diabetes, be sure to specifically discuss with your doctor how these pills interact with B12.

VERDICT: Most people can take phentermine and B12 together, but you need to ask your doctor. B12 supplements can interact with some medications, and it’s never advisable to take any new medications or supplements with phentermine before clearing them with your doctor and pharmacist first.

Instead of B12 Supplements

Rather get an energy boost from food or exercise instead of a supplement? Check out the tips below to boost energy and metabolism naturally!

  • Prioritize sleep. Research shows that getting enough sleep helps you eat less, resist cravings and maintain higher energy levels. All of those effects also help you lose weight!
  • Eat regularly. Your metabolism functions better and faster when you eat enough calories and snack frequently. Avoid skipping meals and aim for at least 1200 calories per day (or 1500 calories per day if you’re a man) to keep yourself going strong.
  • Break a sweat. Getting in shape and building more lean muscle mass will help you burn more calories at rest. Plus, people who exercise regularly report higher average energy levels than their sedentary counterparts.

supplements with phentermine and CLA

Phentermine and CLA Supplements

After a couple months on phentermine, many people start looking for a way to boost their results – on the scale, in the gym and otherwise. This is where CLA comes in! While there is no listed interaction between phentermine and CLA, the golden rule still applies: always ask your doctor and pharmacist before combining any new medication or supplements with phentermine.

What are CLA supplements used for?

Conjugated linoleic acid supplements, or CLA supplements, may help reduce body fat and weight when used in combination with regular physical activity. Scientific research is still mixed as to the effectiveness of this supplement, but many first-hand reports passionately support the use of CLA to reduce body fat. Studies are also mixed regarding the supplement’s possible negative effects with long-term use, namely related to worsening lipid profiles or glucose metabolism. [6] For this reason it’s important to do your own research and assess whether CLA would prove beneficial for you in particular.

Can I take phentermine and CLA together?

Yes, but still ask your doctor and pharmacist. This supplement may help boost weight loss, especially fat loss, during your phentermine journey. Some users feel it’s especially effective in increasing inches lost when used in combination with regular physical activity. Still, it’s vital that your medical team remains aware of all medications and supplements in your daily routine. Check with them before starting CLA.

VERDICT: Many people take phentermine and CLA together without issue, and happily reap the fat-burning supplement’s benefits, but you should still ask your doctor and pharmacist before purchasing a CLA supplement. Your healthcare team knows your case best, so they are best able to advise you as to whether CLA would be helpful in your specific case.

If you and your medical team decide that CLA could benefit your weight loss journey, we recommend 5 Star CLA as one of the best brands on the market. This product contains CLA derived from safflower oil with a minimum concentration of 80%, the industry standard. To read more about 5 Star CLA or order now, click here.

Instead of CLA Supplements

CLA not for you? Consider these tips to help slim down and burn more fat naturally:

  • Incorporate fat-burning foods into your daily diet. Try adding ginger, turmeric, cayenne pepper, cinnamon or any of these other weight loss foods to your meals!
  • Build muscle. Lean muscle mass burns more calories at rest than fat mass, so work towards modifying your body composition to include more lean muscle and less body fat. Here are
  • Workout your core to tighten the muscles under your tummy. Not sure where to start? Check out these 5 core-strengthening exercises for beginners.

supplements with phentermine capsicum

Phentermine and Capsicum (Cayenne Pepper) Supplements

Food-based supplements have earned a certain fame in the past few years. One of the most popular, and most researched, food ingredient supplements is capsicum. It’s a chemical derived from hot chili peppers and studies show it accelerates metabolism to promote weight loss.

What is capsicum used for?

Capsicum helps suppress appetite, curb cravings and boost metabolism. Research shows that adding just a small amount of cayenne to food helps people eat less and curb cravings. These effects are especially strong if you don’t usually eat a lot of spicy food. [7]

More, this same substance boosts metabolism to help you burn more calories – even at rest! Ever felt that rush of heat when you eat something really spicy? Capsicum, like any spicy food, naturally increases core body temperature. Since your body likes to exist at a fairly exact temperature, your metabolism quickly revs to bring your core temperature back down to normal. Through this mechanism, capsicum boost metabolism and promote weight loss. In a scientific study, subjects had higher resting energy expenditure for a whole 4.5 hours after taking the capsicum supplement or eating cayenne pepper!

Can I take phentermine and capsicum together?

Capsicum, in the form of cayenne pepper, is a popular ingredient in foods like curries, chili and seasonings. There is no listed drug interaction between phentermine and capsicum, however this does not mean than an interaction cannot occur. If you want take capsicum as a supplement make sure to double-check with your doctor and pharmacist first.

VERDICT: Ask your doctor and pharmacist before combining capsicum supplements and phentermine. General advice is to start with a very low dose (similar to what you would add to food) and then increase gradually if you tolerate the supplement well. Capsicum may also interact with some drugs and medications, so you should discuss the combination with a medical professional before starting.

If your doctor and pharmacist approve of you taking capsicum supplements with phentermine, consider 5 Star Fat Burner. This supplement contains Capsimax® (cayenne pepper fruit extract) and GreenSelect® Phytosome® (green tea extract) as its two key components. These ingredients are clinically-proven to promote weight loss. Plus, 5 Star Fat Burner is naturally caffeine-free and formulated with five other supporting ingredients to encourage further weight loss. To read more about 5 Star Fat Burner or order now, click here.

Instead of Capsicum Supplements

Not interested in taking capsicum supplements, but still want to reap the natural substance’s fat-burning benefits? Research showed that subjects benefited similarly (or even more!) from eating spicy food instead of taking capsicum supplements. If you can handle the heat, consider adding some spice to your food in order to reduce appetite, control cravings and boost metabolism.

Do you take any supplements with phentermine? Share your questions, concerns and experiences with us in the comment section below!



  1. National Sleep Foundation. (2018). What Is Melatonin?  Retrieved from
  2. WebMD. (2017). What Is Melatonin?  Retrieved from WebMD:
  3. Fetters, K. A. (2017, Nov 12). What Are Pre-Workout Supplements — and Do You Need Them? Retrieved from
  4. Office of Dietary Supplements. (2018). Vitamin B12. Retrieved from National Institutes of Health: Office of Dietary Supplements:
  5. Bauer, D. B. (2018). Are vitamin B-12 injections helpful for weight loss?  Retrieved from Mayo Clinic:
  6. Lehnen, T. E., Ramos da Silva, M., Camacho, A., Marcadenti, A., & Lehnen, A. M. (2015). A review on effects of conjugated linoleic fatty acid (CLA) upon body composition and energetic metabolism. Journal of the International Society of Sports Nutrition, 36. Retrieved from
  7. Ludy, M., & Mattes, R. (2011). The effects of hedonically acceptable red pepper doses on thermogenesis and appetite. Physiology & Behavior, 251-258. Retrieved from


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