The hair supplement market generates $1.5 billion annually in the United States despite limited controlled evidence for most products. If you are spending $50-200 per month on a stack of supplements, you deserve to know which ones are actually contributing to your hair density and which are expensive urine. The only way to answer that question is a structured elimination protocol paired with consistent density tracking.
This guide ranks common hair supplements by evidence strength, then walks you through a systematic process to test each one individually.
The Evidence Hierarchy: Ranking Hair Supplements
Not all supplements are created equal. Here is an honest ranking based on published clinical evidence:
Tier 1: Correct a Deficiency (Strong Evidence When Deficient)
| Supplement | Evidence When Deficient | How to Test | Hair Impact |
|---|---|---|---|
| Iron (ferritin) | Strong | Blood test: ferritin below 40 ng/mL | Deficiency causes telogen effluvium |
| Vitamin D | Moderate-strong | Blood test: below 30 ng/mL | Low levels associated with increased shedding |
| Zinc | Moderate | Blood test or dietary assessment | Deficiency causes diffuse thinning |
These supplements have clear evidence, but only when you are deficient. Taking them without a confirmed deficiency is unlikely to improve density. Get blood work before supplementing.
Tier 2: Some Positive Data (Moderate Evidence)
| Supplement | Evidence Level | Mechanism | Typical Dose |
|---|---|---|---|
| Saw palmetto | Moderate | Partial DHT inhibition (weaker than finasteride) | 320mg daily |
| Pumpkin seed oil | Limited-moderate | Possible 5-alpha-reductase inhibition | 400mg daily |
| Marine collagen | Limited | Amino acid supply for follicle matrix | 10-15g daily |
Saw palmetto has the most data in this tier, with a few studies showing modest improvements in hair count. It blocks DHT at perhaps 30-40% the potency of finasteride (1mg daily, which halts loss in 80-90% and produces regrowth in 65% of users). For a deeper look, see the saw palmetto for hair loss evidence review.
Tier 3: Popular but Weakly Supported
| Supplement | Evidence Level | Reality Check |
|---|---|---|
| Biotin | Limited (unless deficient) | Deficiency is rare in normal diets |
| Collagen | Limited clinical evidence | Strongest evidence is for skin, not hair |
| MSM | Very limited | Minimal controlled hair data |
| Horsetail extract | Very limited | Silica content is theoretical benefit only |
| Viviscal (marine protein complex) | Limited | Proprietary blend, small studies |
The Elimination Protocol: Finding What Works for You
Step 1: Get Blood Work
Before testing any supplements, check your baseline levels for:
- Ferritin (iron stores)
- Vitamin D (25-hydroxyvitamin D)
- Zinc
- Thyroid panel (TSH, free T4)
- Complete blood count
If any values are deficient, correct those first with targeted supplementation. Deficiency correction is not a supplement experiment; it is medical treatment. Work with your doctor on appropriate doses.
Step 2: Establish a Clean Baseline
If you are currently taking multiple supplements, this is the hard part. Stop all non-essential supplements for 8 weeks. Continue any prescribed medications (finasteride, minoxidil) and any supplements correcting confirmed deficiencies.
During this washout period, take density measurements with myhairline.ai at weeks 0, 4, and 8. These three readings establish your no-supplement baseline trend.
Step 3: Add One Supplement at a Time
After your washout, add a single supplement. Choose the one with the highest evidence tier that you have not already ruled out via blood work.
Recommended testing order:
- Saw palmetto (320mg daily) for 4 months
- Marine collagen (10-15g daily) for 4 months
- Biotin (2,500-5,000mcg daily) for 4 months
Measure density monthly. At the end of each 4-month period, evaluate:
- 5%+ density increase over baseline trend: Keep this supplement. Add it to your confirmed stack.
- Under 5% change: This supplement is not producing measurable results. Remove it and move to the next.
Step 4: Build Your Evidence-Based Personal Stack
After testing each supplement individually, your final stack contains only the supplements that produced measurable density improvements in your tracking data. For most people, this stack is smaller (and cheaper) than what they started with.
Separating Supplements from Primary Treatments
If you are on finasteride or minoxidil (5% topical, 40-60% regrowth, onset at 4-6 months), those treatments dominate your results for the first 12-18 months. Running supplement experiments during this period is a waste of time because you cannot distinguish supplement effects from primary treatment effects.
Wait until your primary treatment has plateaued. Plateau means your density readings have been stable (within 3% variance) for 3 consecutive monthly measurements. Only then can you introduce supplements and attribute changes to the new variable.
For a comprehensive hair loss supplements evidence review, read our detailed guide covering each supplement's clinical data.
The Cost of Not Tracking
Consider a typical untracked supplement stack:
| Supplement | Monthly Cost |
|---|---|
| Biotin | $10 |
| Collagen peptides | $35 |
| Saw palmetto | $15 |
| Viviscal | $40 |
| Multivitamin (hair formula) | $25 |
| Total | $125/month ($1,500/year) |
Without tracking, you have no idea if any of these are doing anything. With tracking, you can identify the one or two that actually work and cut the rest, saving $50-100 per month while maintaining (or improving) your results.
Start Your Elimination Protocol
Capture your clean baseline density scan for free at myhairline.ai/analyze. With monthly measurements, you will have your first supplement verdict in 4 months and a fully optimized, evidence-based personal stack within a year.
Medical disclaimer: This article is for informational purposes only and does not constitute medical advice. Supplements are not FDA-approved treatments for hair loss. Do not discontinue prescribed medications without consulting your doctor. Get blood work before supplementing with iron, vitamin D, or zinc. Consult a board-certified dermatologist for clinical evaluation and treatment recommendations.