Finasteride With Biotin, Collagen, or Hair Vitamins: What's Worth Adding

By the Finasteride Fast editorial team · researched from published studies and FDA labeling; not reviewed by a clinician

The supplement aisle sells a lot of hope next to the hair-loss shelf. Here is what the evidence supports, what it doesn't, and the one biotin risk most buyers never hear about.

Short answer: for most men on finasteride, biotin, collagen and general "hair, skin and nails" vitamins are unlikely to add anything measurable. Biotin deficiency is rare in people eating a normal diet, and the evidence for biotin in hair growth comes mostly from case reports. Large doses of biotin can also distort common blood tests, including thyroid and heart tests. Where supplements may help is in correcting a real deficiency, such as low iron, which is something to test for rather than guess at. A 2023 systematic review found some evidence of potential benefit for a few specific products, but the overall quality was limited.

Biotin: popular, rarely needed, and a lab-test problem

Biotin (vitamin B7) has become the default hair vitamin. According to the National Institutes of Health Office of Dietary Supplements (ODS):

• Deficiency is rare. Severe biotin deficiency has never been reported in healthy people eating a normal mixed diet. Higher-risk groups include people with the inherited disorder biotinidase deficiency, people with chronic heavy alcohol use, and pregnant or breastfeeding women.
• The hair evidence is thin. ODS describes claims for hair, skin and nail benefits as supported, at best, by only a few case reports and small studies. The hair reports it cites involve children with a rare hair condition, not adults with pattern hair loss.
• You need very little. The adequate intake for adults is 30 micrograms a day. Many hair supplements contain thousands of micrograms.

Collagen

Collagen supplements are marketed for skin, joints and hair. Hair is made mostly of keratin, not collagen, and the body breaks swallowed collagen down into amino acids like any other protein. Collagen wasn't among the supplements the 2023 systematic review found associated with potential benefit for hair loss. If you eat enough protein, there's no strong reason to expect collagen to add anything to finasteride. If your diet is very low in protein, fixing the diet is the better first step. Collagen is generally well tolerated, so the main cost is money. If you like it for other reasons, there's no known conflict with finasteride. Just don't expect it to change your hair count.

What a 2023 systematic review found on hair supplements

The most useful single overview is a systematic review in JAMA Dermatology (2023) by Drake and colleagues. It looked at nutritional supplements for hair loss in people with no known deficiency.

• It included 30 studies: 17 randomized trials, 11 non-randomized studies and 2 case series.
• Among the higher-quality studies, a number of products were associated with potential benefit, including branded blends (Viviscal, Nourkrin, Nutrafol, Lamdapil, Pantogar), capsaicin with isoflavone, omega-3 and omega-6 with antioxidants, an apple nutraceutical, zinc, tocotrienol and pumpkin seed oil.
• Some others, including vitamin D3, had only low-quality evidence.
• Side effects were rare and mild.
• The authors described a "potential role" for supplements, recommended shared decision-making, and called for larger randomized trials against active treatments.

Two points get lost when supplement brands quote this review. First, "potential benefit" in small studies isn't the same as evidence comparable to finasteride. Finasteride was approved on placebo-controlled trials in more than 1,800 men. Second, none of these products was shown to add to finasteride. Most were tested on their own, often in small groups. Pumpkin seed oil and saw palmetto are covered in more depth in our natural DHT blockers ranked by evidence.

Deficiencies worth testing for

Here supplements can genuinely matter, because correcting a real deficiency can help hair that's thinning for reasons finasteride doesn't address. MedlinePlus lists anemia and thyroid disease among causes of hair loss. Heavy shedding after illness, surgery, crash dieting or major stress (telogen effluvium) is another common cause that finasteride won't fix.

If you've lost weight quickly, our article on rapid weight loss and hair explains how telogen effluvium differs from pattern loss.

"DHT-blocking" blends on top of finasteride

Many hair supplements advertise saw palmetto or other plant extracts as natural DHT blockers. If you already take finasteride, a prescription drug designed and tested to reduce DHT, adding a weaker, less predictable product aimed at the same enzyme has little obvious upside. No trial we know of has shown it adds benefit. It also makes it harder to tell what's causing a side effect if one appears. If you want to take one anyway, tell your prescriber and pharmacist so it's on your medication list.

What about an ordinary multivitamin?

A standard multivitamin at normal doses is a reasonable choice if your diet has gaps, for general health. It isn't a hair treatment. Check its biotin content, because some "men's" and "beauty" multivitamins now include far more than the adequate intake. Mention it before any blood test. Avoid stacking several products that each contain the same vitamins or minerals. Doses add up quickly, and some, such as vitamin A and zinc, are harmful in excess.

A buying checklist

What's more worth your money

If you want to add something to finasteride, the options with the most evidence are medicines, not vitamins. Minoxidil is the main one; see best hair loss treatments ranked by evidence. Ketoconazole shampoo is a low-cost non-prescription add-on that some men use for scalp health. The evidence for it in pattern hair loss is limited compared with finasteride or minoxidil; our finasteride and ketoconazole article sets out what's known. A good diet, enough protein, and treating any real deficiency will do more for most people than an expensive hair gummy.

When to see a doctor: if your shedding is sudden or heavy, comes with fatigue, feeling cold, or other symptoms, or follows illness or rapid weight loss, see a doctor for blood tests before buying supplements.