I’m sorry, I just saw the thread title and posted without reading. 
My wife has started using prenatal vitamins and I believe a biotin supplement in addition to some sort of spiky hair thingy she keeps in the shower.
I don’t know what it is, all I know is that it feels good when I use it on my head. 
I used to drink a lot of bone broth but then I got sick of making it and kind of sick of drinking it. As soon as I stopped, my nails, which had always been strong and healthy became brittle and my hair started falling out. So I began throwing a tablespoon of grass fed gelatin (Great Lakes brand) in my morning coffee and giving it a whir with a stick blender. My skin rehydrated, my nails strengthened and my hair stopped falling out. I even have new baby hairs sprouting throughout my scalp. Using gelatin over collagen drink mixes means I don’t have to buy another product for a specific purpose, as I use gelatin in a variety of cooking and baking recipes as well.
I have used Vital Proteins & Swanson Vitamins house brand for years - no breakouts (but I am not sensitive to breakouts).
I definitely noticed an improvement in my nails first (never had to file my nails down in my life), skin (people compliment my face asking what I am doing differently) and my hair is growing a lot faster… I cannot say it is thicker… I also do biotin & a castor oil mask once a week on areas that are thinner.
I might have to try putting beef gelatin in my coffee. Good idea, thanks.
Just take a gel cap every day, I get mine on amazon as 1000mg and take one daily.
I posted this on another thread about hair loss over a year ago. It was my theory as to why I was losing hair.
https://www.ketogenicforums.com/t/hair-loss/5829/53?u=virginiaedie
This past summer, when I did my first attempt at carnivore, I went through another period of hair loss. When I changed to carnivore, I just couldn’t eat that much and so I think I, once again, had a calorie/nutrient deficit.
I’m eating more now that I’m adjusted and the hair loss stopped. It is also starting to fill back in since I have a lot of little stubby hairs sticking out all over the place.
I would take an honest look at how nutritious your food intake is.
I inherited a 10g pack of gelatin from a friend who moved. So I thru it in my coffee slurry this morning. I’m going to have to track down some more to test it long enough to see if it helps. Almost two years on keto, I feel like my nails are finally getting stronger, but if gelatin in my coffee could make stronger and my hair thicker, I’m all for that! And probably easier to find and more affordable than collagen supplements. Thanks for the idea!
If you have the means to, I strongly recommend you get your levels of DHT (dihydrotestosterone) hormone in your blood tested. It is not uncommon for weight loss (or gain for that matter) to trigger hormonal imbalances, particularly in women. If this is indeed the case, no amount of topical treatments will ever help you.
I’ll spare you most of the medical talk, but when you have high levels of DHT it attaches to your hair follicles, depleting them of oxygen and nutrients, basically asphyxiating them from within, which in time results in hair thinning and eventually hair loss. It’s true DHT is an androgen (male) hormone, but it doesn’t mean women are spared. Your glands can secrete it excessively in times of stress, imbalances and/or illness.
Conventional medicine has approved effective treatment (like Finasteride) for high DHT and hair loss, but it comes with serious side effects. Natural, safer inhibitors for the 5α-Reductase enzyme which facilitates DHT synthesis are: Zinc, Saw Palmetto and Pygeum. Also, I’ve seen high rates of success by maintaining optimal levels of Magnesium and Silica through bio-available supplements in addition to what I just mentioned.
I’d say you get some blood-work done. You really got nothing to lose. Other than your hair that is. 