About Japanese Energy Drinks

Popularity
According to this site, http://ranking.goo.ne.jp/ranking/099/nutritivedrink/(it's in Japanese), the energy drinks that are bought most by consumers are:
  1. Lipovitan D
  2. Tiovita(pronounced "Chiobita")
  3. Yunker(pronounced "Yunkeru")
  4. Alinamin
  5. Regain
  6. S-CUP
  7. Guronsan
  8. Shin-Guromondo
  9. Aspara-Drink
  10. Zena
Categorization
Energy drinks in Japan can be categorized in to three groups:
  • 医薬品(Pharmaceutical drug) 
  • 指定医薬部外品(quasi-drug: medications that are milder in effect than regular drugs and are safe to be purchased without advice from pharmacists). 
  • 炭酸飲料(Carbonated Beverage)
The energy drinks listed on the top would all fit into the category of quasi-drugs(Some of the brands also sell "carbonated beverage" energy drinks). In fact, the Japanese term for energy drink, "eiyou dorinku(栄養ドリンク)" often refers to the quasi-drugs and pharmaceutical drugs and not the carbonated beverage types(there are exceptions though). The carbonated types are usually referred to as "Enajee Dorinku", the Japanese katakana pronunciation of "Energy Drink". Since there is no exact translation for "eiyou dorinku", the term, "energy drink" is used to refer to all of these types of energy drinks on this site.

How to recognize a quasi-drug energy drink
Quasi drug energy drinks usually come in the form of a small  brown glass bottle. The brown color is added to help prevent the breakdown of amino acids and vitamins inside. Consumption is usually limited to once per day for people aged 15 and older. This is in sharp contrast to carbonated energy drinks (such as Red Bull) which usually come in cans and plastic bottles with no limitations on how much to drink per day. There may be pharmaceutical energy drinks that may look similar to quasi-drugs but you can often tell the difference from the price and packaging. Remember, quasi-drugs are sold in convenience stores, pharmaceutical energy drinks are not. (However, there are a few convenience stores which have a certified pharmacist and will sell medicine.)

How to recognize a pharmaceutical energy drink
The pharmaceutical ones usually include ingredients used in Kampo(Traditional Chinese medicine in Japan) such as ginseng and often contain more Vitamin B(1,2,6,12) compared to quasi-drugs. They are also usually more expensive and come in neat packages even if there is only one bottle inside.

Where to buy
You will probably only find pharmaceutical energy drinks only in drug stores in Japan. In contrast, quasi drugs and "carbonated beverage" energy drinks can be found readily in convenience stores.

The energy drinks below show the label, "指定医薬品部外" which refers to "quasi drugs".
 S-CUP
Lipovitan D 11

 TIOVITA