In the middle of the sixth century, in Constantinople, the emperor Justinian I wanted silk of his own. According to the historian Procopius, some monks came to him with a plan. They travelled east, hid silkworm eggs inside their walking staffs, and carried them home, ending a monopoly that China and Persia had held for centuries. Sources disagree on the exact year, so I will only say it happened during Justinian's reign. It is a spy story about a fibre. Silk was that valuable.

BioSilk borrowed some of that mystique in 1986. The company behind it, Farouk Systems, is based in Houston and was founded that year by a hairdresser, Farouk Shami, who also created the CHI ceramic iron. Farouk Systems says he was the first to use silk proteins in a line, the Silk Therapy line, and BioSilk's own copy says each silk protein contained 17 of the 19 amino acids found in hair. I like a product with a clear point of view, and this one has stayed on its shelf for decades. To be fair, the ingredient list tells a fuller story: it leads with silicones, with hydrolyzed silk further down, so the silicones do the visible shine and the silk is the story.

The trick is to know which bottle does which job. Silk Therapy Original is the classic, a weightless leave-in the brand says repairs, smooths and protects all hair types. There is a version with Organic Coconut Oil, and a Lite one for anyone who worries about weighing hair down. Shine On is a spray for a fast finish, and Thermal Shield is the one to reach for before a hot tool. The line also has a Shampoo, a Conditioner and a Silk Therapy 17 Miracle Leave-in Conditioner, so you can build a routine inside a single brand.

Here is how I would choose a shine product: look at your hair in daylight, then decide whether you want gloss or you want it smoother. They are not the same thing. Gloss reflects light, and smooth is what stops the frizz. Most bottles do a bit of both, and the label tells you which one leads.

Drybar's Liquid Glass is named for the glass hair look, a high-gloss finishing serum. Moroccanoil Treatment Light is the oil for fine hair, and RŌZ makes a Milk Hair Serum, which I read as the softer, less slick idea of shine. Oribe's Gold Lust is a nourishing oil aimed at frizz. Davines' Heart of Glass is a bonding glow serum, so it is doing something between styling and repair.

OUAI's Hair Oil is the simple one. Crown Affair's The Radiance Hair Oil promises frizz-free shine, and Color Wow's Pop + Lock is a frizz control and glossing serum. Compare them with the BioSilk bottles in the first grid: the older formulas coat the hair, and the newer ones often add a bonding or conditioning story on top.

A pairing I like: a few drops on damp ends before drying, then a tiny amount on dry hair at the end. Two light layers beat one heavy one.

What I would skip: a rich oil on fine hair on a humid morning. It will look flat by lunch.

Start with the pillowcase. It is the least glamorous change on this page and the one you will use every night. A smooth surface is kinder to hair than a rough cotton one, and it is the easiest habit to change, since it needs no time in the morning.

Slip's Pure Silk Queen Pillowcase comes with lace trim in Sweetie, and Lashify, better known for lashes, makes a Silk Pillowcase. Slip's Skinny Scrunchies and Silk Hair Wrap round out a small silk set, one for the day and one for bed.

Then the bonnets. KISS makes two, a Silky Satin X-Large Bonnet Cap in black and a Tie Band Braid Edge Bonnet in Dust Pink, the second for people who care about their edges and braids. The Steam Bar has a Satin Sleep Bonnet, and Sleepy Tie makes The LuxeBonnet.

A pairing I like: a light serum on the ends before bed, a bonnet or a silk wrap over it, and a silk pillowcase underneath. It sounds like a lot, and it takes ninety seconds.

What I would skip: a tight scrunchie in your sleep. A loose one on the outside of a wrap is better.

A habit worth borrowing: put the protectant on damp hair, before the dryer, and comb it through so it reaches every layer. A spray on already-dry hair is a good top-up, but it is not a shield.

Kérastase's Genesis Heat Protecting Leave-In is made for weakened hair, and Ebb Ocean Club's Hair Barrier Repair Oil aims at shine and heat protection in one bottle. Oribe's Imperial Blowout is a styling cream, the one for a proper blowout with a round brush. UNITE Hair's 7SECONDS is a glossing spray, quick and light.

JVN's Complete Instant Recovery is a leave-in serum, Olaplex No. 9 Bond Protector is a serum for frizz and heat, and Davines' LOVE Smoothing Perfector is aimed at frizzy hair. Kenra Professional's Silkening Gloss is a heat protectant shine serum, which brings the whole idea back to silk. BioSilk's own Thermal Shield from the first grid is the one to compare with them.

A pairing I like: a cream or leave-in on damp hair, and a shine serum after styling. The protection goes first and the gloss goes last.

What I would skip: any heat tool set to its highest setting just because you are in a hurry. Lower the temperature and use the protectant.

I think BioSilk earns its long life by being honest about what it is: a quick shine serum with a silk story, from a hairdresser. I would keep Silk Therapy Original for finishing, a heat protectant for the days I use a hot tool, and a silk pillowcase for the nights.

A drop on the ends, not the roots, and you are done. Skip the extra pump; a little goes a long way, and the shine comes from the finish, not the amount. If your hair is fine, start with Lite and see how it behaves by evening. The monks needed hollow staffs to move silk. You only need a pump. If you want to keep browsing, I also put together The Silk Bonnet and Chanel Rouge Coco Flash.