Diagnostic and medical care equipment and consumables. Free delivery over £200, otherwise according to weight - typically starting at £2.99.
Foot health and shoe care. Prices are plus VAT and delivery is at cost.
Prescription classic, safety and designer glasses and accessories. Sizing guide and catalogue available. Prices include delivery 
Health supplements and aids, such as Megavent to help stop snoring. Also lots of information and recipes. First class UK delivery £2.50 per order.
Vitamins, probiotics and other health supplements with frequent offers and discount codes. Free UK delivery on all orders.
Vitamins, minerals and supplements. Frequent large discounts. Online guides to nutrition and fitness. Delivery £1.99 to mainland UK.
Supplements that are as close as possible to natural foods. Free UK delivery over £25, otherwise £1.95 per order. 
Health & beauty products with an emphasis on health, including medicines. Free delivery to the UK over £45, otherwise £2.95 per order.
Health products, cosmetics gifts, often at seriously reduced prices. Standard UK delivery free on orders over £35 otherwise £3.
Vitamins, minerals and supplements for health care, joint care and to aid weight management. Also health notes. Free delivery to UK
Food intolerance finger prick blood test. Find out which food is making you ill. Also other allergy and body wellness tests.
Men's Health
first 3 issues for £1
(12 month subscription)
Holland & Barrett are best known from their TV adverts and High Street shops for vitamins, essential minerals and food supplements, but they also offer information on the web site. There is a complete vitamin guide, advice related to specific health conditions and to nutrition-related sport and fitness. They deliver worldwide, but their charges for posting abroad a quite high. UK mainland delivery is £1.99.
Healthy Direct sell similar vitamin and health supplement products. Products can be found by clicking on one of a choice of conditions you are seeking to treat. Post is free on all orders and there are frequent extra discounts.
Vitamins Direct focus on vitamins and supplements but also have products for weight management and a link to advice on health care called 'Health Notes'. They deliver free to the UK.
Nature's Own also concentrate on vitamins and natural supplements. They try to avoid artificial compounds, instead blending ingredients that are 'as close as possible to natural foods'. They charge £1.95 for UK delivery if your order is under £25, otherwise it is free.
First Aid Warehouse, sell medical furniture and diagnostic equipment including blood pressure monitors. They take NHS orders and supply GPs and clinics as well as households. Pharmacy2u can supply medications. Both sell creams, ointments and other similar preparations for health care and improvement.
Glasses Direct make and deliver glasses to your prescription. They have lower overheads than the traditional High Street opticians and they pass the savings on to customers. Glasses are available from £15. Designer, rimless, bendable, safety and several other kinds of glasses are available, as well as cleaning materials, cases etc. They provide a sizing and fitting guide and a money-back guarantee. They have a catalogue or you can see their range online. They even have a system that lets you upload a photo of yourself and see how the glasses would look on you.
PreventX supply kits for preventative testing. They have tests for prostate cancer, cholesterol, fertility and even common recreational drugs. Yorktest have kits that enable you to test for food intolerance, other allergies, liver function etc. They also have books on food and health issues. Or for something really specialist, Foot Health Care sell all sorts of things for your feet, from creams and lotions to socks and insoles, from footcare tools to shoe care.