How can one measure if vitamins are really helping a patient to delay hair loss?

Question

(Inspired by an answer to a different question on a related topic.)

I'm guessing there would have to be a period to measure the current rate of hair loss before making changes on current diet and habits and after that period the patient would start the new prescribed diet and/or habits and we would continue to monitor/measure in order to calculate a new rate of hair loss. And as a result we would have an actual record of improvement (if any).

So what would be used to measure what and how?

Answer 1

The absolute key to know if ANY treatment is working would be to find out that things get better after such treatment started, in this particular case, you want hair-loss to decelerate.

In order to register a change, you need to first register the previous state of affairs, so you'd have to calculate hair-loss rate both before and after the treatment was started.
First of all you wanna be sure it is actually a problem or if it isn't at all.
If the rate of hair loss is not accelerating in a way that indicates some pathological problem, then there wouldn't be anything to worry about because humans normally lose some hair and grow some new.
Otherwise, if the hair is falling in an accelerating manner and the amount of new hair does not correlate, then a diagnose of the cause and a treatment may be necessary.

The cause is beyond the scope of this question so I'll stay on topic by elaborating on measurement and calculations.

This calculations shouldn't be done by means of human perception (e.g. photographs or simple observation) you want a method that's less fallible, there are other suggested "practical" methods like wearing a cap all day and then count the amount of hair that stays on the cap when you take the cap off and when you take a bath, this kind of methods are messy and there are multiple chances where mistakes can be made, so I'd say error-prone methods like this are useless. Not to mention, wearing a cap at all times is not practical and may even make things worse.

I found some very interesting articles licensed under Creative Commons in the National Library of Medicine. The first one describe a variety of methods, ranging from non-invasive to semi-invasive to invasive.

Non-invasive methods

e.g., Questionnaire, daily hair counts, standardized wash test, 60-s hair count, global photographs, dermoscopy, hair weight, contrasting felt examination, hair feathering test, phototrichogram and TrichoScan.

Semi-invasive methods

e.g., Trichogram and unit area trichogram (UAT).

Invasive methods

e.g., Scalp biopsy.

A scalp biopsy seems way to invasive and not suitable to be doing it frequently in order to calculate a rate of acceleration/deceleration, so I investigated further on the Thrichogram option; it turns that method has been used and approached from different angles since the 80s:

This personal technical adaptation gives an easily obtainable definition of five quantitative parameters analysing the hair on a given area of the scalp: density of implantation, telogen percentage, growth rate, mean anagen diameter and percentage of fine hair less than 40 mu in diameter. In the normal male adult our measurements gave the following results on the vertex: density 204 +/- 10 hair per square centimeter, telogen percentage 17.8 +/- 2.8 p. 100, growth rate 0.35 +/- 0.03 mm p. day, mean anagen diameter 76 +/- 5 mu, percentage of fine hair 9.2 +/- 1.8

And there seems to have been some progress recently in the development of instruments to aid in such methods:

To properly assess the progression and treatment response of alopecia, one must measure the changes in hair mass, which is influenced by both the density and diameter of hair. Unfortunately, a convenient device for hair mass evaluation had not been available to dermatologists until the recent introduction of the cross-section trichometer, which directly measures the cross-sectional area of an isolated bundle of hair.

The article mentions one particular trademarked device but there must be others. So there you have it, I'll venture to state with some confidence that the best approach is to use some device like that one and measure your scalp at least one time a day. And for security sake and professionalism sake, I'd recommend some expert assistance from a dermatologist. But if you have a Scientific Mind and a Hacker Spirit, do it yourself, why not.
(Just the measurement part, don't diagnose yourself.)

So in this particular case, if vitamins don't decelerate your hair loss rate, then to hell with vitamins, you may need something else, so go to a doctor and get properly diagnosed.

Answer 2

I can think of multiple ways.

1. One of the important manifestaions of hair loss is development of baldness. So if there is such a manifestation, (such as development of male pattern baldness or any growing bald spot), the area of it can be successfully measured, and the rate of growth of area can be a measure of hair loss.
2. If that kind of thing is absolutely necessary, the person can wear a cap around his head all day long. By measuring the amount of hair inside that cap, a rough measure can be made. (this can be done on a bath to bath 24 hour basis).

Even after doing all these, there will always be the question of how useful that will be, because absolute hair loss depends on a large number of factors. And there may not even be a large or measurable difference pre or post treatment.