What to Do If Phentermine Causes Hair Loss

by Rakib Sarwar, RPh on May 13, 2024
Last updated on May 13, 2024

So many articles miss the boat on highlighting hair loss as a side effect of phentermine. Yet, the sight of extra hair on the brush for a ton of gals suggests those sneaky factors like major hormone shifts and rapid weight loss with phentermine might be the hidden reasons behind their thinner manes (5). If you’re nosy about why your hair is saying “bye-bye” and hunting tips to keep your tresses thick and shiny, hang tight. You’re about to learn some secrets that could blow your mind.

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Hair loss linked to phentermine intake is known as alopecia, and typically starts from 3 months into the weight loss treatment with phentermine. Ironically, this can often be when the powerful beneficial effects of phentermine begin to wear off or stop working for some patients. This hair loss can continue unabated for as long as you are on the drug. Most of the cases of hair losses that occur in people trying to lose weight with phentermine are often caused by dietary changes. Some of these dietary changes include eliminating foods or restricting calories, as well as the striking hormonal changes known to accompany phentermine intakes (5).

Phentermine’s damage on your hair is not always easily noticeable initially. After the damage is done to your hair, the follicles of your hair can lie dormant for as long as several months before the hair loss becomes noticeable. Most times your body corrects the problem on its own. Most people who have had this case reported seeing little hairs growing out of their scalps a few weeks after noticing the hair loss (5).

The hair loss that occurs with phentermine is the type you experience while brushing or washing your hair. It occurs with your hairs pulling out from their roots and falling off. However, this occurs at a much faster rate than what you would experience normally.

However, if the hair loss is characterized by your hair becoming dry and brittle before breaking away from the roots, it could be a good sign that you have an underlying medical condition. One of the common medical conditions that can lead to this type of hair loss is hypothyroidism. In order to make sure you know where the hair loss is actually coming from, it would be best to speak with your phentermine doctor for medical assessment and attention (5).

What is Phentermine?

Phentermine works well with some approved exercises, behavioral changes, and lowered calorie diet program aimed at helping you lose weight. Phentermine is a popular weight loss drug used by obese and overweight people to lose weight and keep unwanted fats at bay. Such phentermine-induced weight loss goes a long way to minimize the health problems that accompany obesity such as diabetes, heart diseases, high blood pressure, and a shortened lifespan (1, 3).

This weight loss medication helps you lose weight by reducing your appetite, increasing the amount of energy your body uses or by affecting some parts of your brain. Phentermine is a powerful appetite suppressant and a member of the sympathomimetic amines (1, 3).

Common Side Effects of Phentermine

Most people making use of phentermine may not experience any serious side effects. The benefits of taking phentermine will always be greater than whatever health risks and side effects the drug may bring (4).

Some common symptoms of taking phentermine include dry mouth, dizziness, vomiting, diarrhea, constipation, and nausea. If you experience any of the side effects for long, there may need to consult your pharmacist or doctor (4, 6).

Taking phentermine can increase your blood pressure so you may want to check your blood pressure often and let your doctor know if it is higher than the healthy levels (3).

Other common side effects you may experience include irregular heartbeats, hallucinations, agitation, anger, and nervousness. You may also experience some uncontrollable muscle spasms or changes in your sexual urges (4, 6).

Some people, however, experience some more serious side effects such as slurred speech, weaknesses, headache, blurred vision, etc. Some people link this drug to lung and heart problems such as heart valve problems and pulmonary hypertension.

The longer you use phentermine, the higher the risk of experiencing these complications and health problems. If you experience very serious side effects such as fainting, chest pain, feet swelling, difficulty breathing well while exercising, make sure you stop taking phentermine immediately and consult your doctor (4, 6).

Possible causes of hair loss while taking phentermine and remedies

There have been several arguments as to whether taking phentermine causes hair loss or not. However, going by available overwhelming evidence and results, taking phentermine can no doubt make you lose your hair. People found to be at the highest risk of losing hair while taking phentermine are women between the ages of 40-49 years of age (1). But what other factors can account for hair loss while on phentermine? Let’s see some common causes of hair loss which might be related or unrelated to phentermine.


The major component of your hair is protein. So, the moment your body lacks adequate protein, the production, and growth of your hair becomes seriously hindered. When you sum up the effects of the phentermine-induced weight loss, the hormonal changes occurring in your body and the lack of protein, which might explain why you might lose your hair while taking phentermine. To make sure you keep your hair in place while on this weight loss drug, make sure you get adequate daily protein intakes from your diet. The RDA recommends 56g per day protein intake for men and 46g per day daily protein intakes (2).


Researches have shown that 10% of adult females between the ages of 20-49 have iron deficiency-induced anemia (1). And this can be a major cause of hair loss in women when taking phentermine for weight loss. Once you confirm you do have an iron deficiency, the best cause of action would be to head straight to a dispensary store to get your iron supplement and nip the hair loss in the bud. Without an adequate amount of iron in your daily diet, your quest to lose weight might remain an illusion. So make sure you add some good sources of iron such as lean meat and leafy greens to your diet to get the right amount of iron (2).

Vitamin B

Another major known cause of hair loss is vitamin B. However, a hair loss induced by a lack of vitamin B can be easily handled. Most experts advise their patients to get some shots of vitamin B12 while taking phentermine as a source of energy. However, you will benefit more by taking the B- complex multivitamins as today’s American staple diets lack important B-vitamins like folate.

Other major side effects of phentermine such as dry mouth, depression, and anxiety can also be minimized using the B-vitamins. Vitamin B7, known as Biotin is one important B-vitamin that helps discourage hair loss by preventing hair thinning. So if you are prone to losing your beautiful hair while taking phentermine, you may want to consider ensuring you have your B-vitamins handy (2).


Most women who have overweight problems have been found to suffer thyroid-related problems. So, doctors recommend you have your thyroid checked whenever you are faced with weight issues. One of the major effects of such thyroid malfunctions is increased weight and unexplainable hair loss. Using some available synthetic thyroid drugs to bring your thyroid back to normal can bring the hair loss under control even as you try to lose weight with phentermine (2).

Polycystic Ovary Syndrome

Otherwise known as PCOS, this condition is quite similar to the hypothyroidism we mentioned above. PCOS can also induce both weight gain and hair loss as a result of serious hormonal changes. Women with this condition find taking phentermine effective for appetite restoration, weight loss and hair growth (2).

Dramatic weight loss

One major reason why taking phentermine can make you lose your hair is due to its very dramatic hair loss effects. The human body is wired in such a way that it interprets any dramatic or sudden hair loss as some kind of physical trauma that lead to hair loss. To ensure your hair does not go with the weight, make sure you boost your calorie intakes. This will power up your body metabolic processes while fueling your activity levels (2).

Important nutrients that can help you reduce hair loss while on phentermine

To minimize this phentermine-induced hair loss, there are certain steps you can take to keep your hair in top health. One sure way to maintain the healthy condition of your hair is to eat the right foods loaded with nutrients that support your hair growth and health. Here are some of the best healthy diets to maintain healthy hair while taking phentermine to prevent hair loss:

Omega 3 Fatty Acids

Omega 3 fatty acids are known for their ability to support healthy hair growth and regrowth. Eating enough omega 3 fatty acids rich foods will help you maintain the best hair while taking phentermine. Some great sources of these healthy omega 3 fatty acids include oily fishes, olive oil, avocado, etc. Adequate intake of omega 3 fatty acids all week long will help your hair stay healthy and also help you burn unwanted fats and boost your body’s metabolic processes (2, 5).

Zinc and Iron

Zinc and Iron are known to work hand-in-hand to help maintain the health of your hair and help you maintain a healthy body. The ability of these two essential minerals to maintain a healthy body also helps make your weight loss plans more successful. According to experts, eating lean red meats at least 2 times every week will help you maintain an adequate supply of these two important vitamins to your body. Other sources of these nutrients include sesame seeds, lentils, pumpkins, quinoa and cashews (2, 5).

Vitamins C

Vitamin C is known to boost the assimilation of Iron in the body. Eating foods rich in vitamin C will help your body maintain a healthy iron balance for hair growth. Vitamin C is found in abundant supplies in citrus fruits, broccoli, kiwis, red peppers, cantaloupe, and Brussels sprouts. However, you can still get an adequate supply of this healthy vitamin by taking some good weight loss multivitamins sources and supplements (2, 5).


Eating plenty of protein is one sure way to prevent the possibility of your hair falling off while on phentermine. Some great sources of protein include lean meat, dairy products, beans, nuts, etc. Some veggies are also known to be great sources of protein as well (2, 5).

Biotin and Vitamin D

Biotin is yet another great nutrient known to help you keep your hair in place while on phentermine. One great source of biotin is egg. Eggs are also known to contain an adequate amount of vitamin D, and vitamin D has been found to help keep your hair healthy. If you do not love eating eggs, you can get an adequate amount of vitamin D needed to stay healthy and keep your hair strong by spending a few minutes in the sun daily. You can also get the biotin and vitamin D your hair needs to stay healthy from the appropriate multivitamins (2, 5).

Vitamin E

If you are worried about losing your beautiful hair while taking phentermine, it is important you ensure you give your body enough vitamin E. Vitamin E is one important vitamin that helps keep your nails, skin, and hair healthy. Most people do not get an adequate supply of this essential vitamin because it is mostly found in fatty foods such as oils, seeds, and nuts.

These fatty foods are good sources of good fats and can help boost your body metabolism and enhance weight loss. If you do not have access to these foods, you can complement your vitamin E supply by taking over-the-counter multivitamins daily. However, you must ensure you get medical or pharmaceutical advice on what dosage is good for you while on phentermine (2, 5).

Important precautions while taking phentermine

As with every prescription medication, only a qualified doctor can prescribe the right phentermine dosage for you. Make sure you let your doctor know of any side effects or negative reactions from the drug. If you have any medical histories such as glaucoma, diabetes or past case of drug abuse, phentermine should be avoided entirely. Prolonged use of phentermine can lead to very serious drug dependence which may manifest in both physical and psychological addiction (7).

Following doctors instruction, while on phentermine will ensure you enjoy the weight loss benefits of phentermine, stay in good health without losing your beautiful hair.


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One Response

  1. Some important nutrients are listed that can help reduce hair loss. Is that to say that it’s okay to continue phentermine and long as the appropriate nutrients are taken? Or should one stop using phentermine as soon as hair loss is noticed? Is hair loss from phentermine Permanent

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